There are different types of COVID-19 tests.
Only viral tests are recommended to see if you are currently infected with COVID-19.
Viral tests are swab or saliva tests.
Antibody tests (also known as serology tests) are blood tests.
VIRAL TESTS
(swab or saliva tests) |
ANTIBODY TEST
(blood tests) |
||
|
NUCLEIC ACID AMPLIFICATION TEST (NAAT) |
ANTIGEN TEST |
ANTIBODY TEST |
---|---|---|---|
How the test works |
Detects genetic material (RNA) within the COVID-19 virus |
Detects proteins (or antigens) on the surface of the COVID-19 virus |
Detects antibodies made by the immune system |
How the test is done |
Saliva, or swab from nose or throat |
Swab from nose or throat |
Blood from arm or finger stick |
How long it takes to get results |
Same day and up to 3 days. Some are rapid (around 20 minutes) |
Most are rapid, around 10-30 minutes |
Same day and up to 3 days |
Over the counter self-tests |
A few companies make them |
Many companies make them |
Not available |
*Includes PCR (e.g., Reverse-Transcriptase Polymerase Chain Reaction - RT-PCR) and Loop-Mediated Isothermal Amplification (LAMP)
Note: There may be other settings that have their own testing requirements.
If you had COVID-19 within the last 90 days, you should test if you have symptoms of COVID-19. You should also test if you are a close contact to someone with COVID-19 and it has been 31-90 days since your first positive test. Otherwise, testing is not usually recommended. If you do test within 90 days of your first positive COVID-19 test, use an antigen test rather than a NAAT.
Talk with your doctor to make sure you understand what your test result means and any next steps. If you took a self-test, read the manufacturer’s instructions on how to interpret the test results. If you need advice about what to do next, you can also call the DPH COVID-19 information line at 1-833-540-0473.
Your COVID-19 Test was POSITIVE (POS)
The test detected the COVID-19 virus. It is very likely you have COVID-19 and could spread it to others.
You need to isolate. Stay home and away from others for at least 5 days, even if you do not have symptoms. Follow all instructions at ph.lacounty.gov/covidisolation.
Important: If you have symptoms, ask about COVID-19 treatment right away, even if your symptoms are mild. Treatment can prevent you from getting very sick. Many adults and some children qualify for free medicines, such as Paxlovid. The oral medicines must be started within 5 days from the start of your symptoms, so don’t delay. Talk to your doctor or call the Public Health Tele-Health Service 1-833-540-0473 – open 7 days a week, 8:00 am – 8:30 pm. For more information, visit ph.lacounty.gov/covidmedicines.
Your COVID-19 Test was NEGATIVE (NEG)
A negative COVID-19 result means the test did NOT detect the COVID-19 virus at the time you took the test.
If you have symptoms of COVID-19
It is possible that the test is wrong and that you are infected. This can happen for many different reasons including if the test was taken too early, if your specimen sample wasn’t collected well, or if the amount of virus was too low to be detected by the test.
If you used a self-test, take steps to make sure it isn’t a false negative. Make sure you read and follow all test instructions correctly. Repeat the test at least once at least a day later. See FDA instructions on repeat testing.
Follow the LAC DPH COVID-19 guidance at Learn about Symptoms and What to do If you are Sick.
If you don’t have symptoms of COVID-19
It is unlikely you have COVID-19.
If your negative test was a self-test, make sure you read and follow all test instructions correctly. Some self-tests are designed to be used in a series (also known as serial testing). Multiple negative tests increase the confidence that you are not infected with the virus that causes COVID-19. This is especially important if you are a close contact. See FDA instructions on repeat testing.
COVID-19 antibody tests (also known as serology tests) are blood tests that are used to look for antibodies to SARS-COV-2 (the virus that causes COVID-19). If we get COVID-19 or a COVID-19 vaccine our body’s immune system responds. It makes antibodies and prepares our immune cells to be ready to fight the virus in the future.
COVID-19 antibody tests do not look for the actual SARS-CoV-2 virus itself. They can be used to help figure out if someone was infected with COVID-19 in the past. It takes about one to three weeks after becoming infected for the body to make enough antibodies to be found by a test. Some people may take even longer, and some people who were infected with COVID-19 may never develop antibodies. NONE of the currently authorized tests are recommended to see if people have been successfully vaccinated against COVID-19.
COVID-19 antibody tests cannot tell a person:
Antibody tests are not 100% accurate, so false results may occur. Talk to your doctor before being tested for antibodies. Your doctor can help you decide if you should be tested and, if you are tested, tell you what your results mean. To learn more about antibody tests, visit the CDC webpage.